Clip unit

ABSTRACT

A clip unit including: a clip main body having a first arm portion, a second arm portion, and a middle portion; a pressing tube formed in a tube shape to be capable of accommodating the clip main body, the pressing tube being provided to deform the clip main body so as to make a distal end of the first arm portion and a distal end of the second arm portion to approach to each other, as the middle portion, the first arm portion, and the second arm portion are moved toward a proximal end side of the clip unit; a locking portion configured to protrude from an inner circumferential surface of the pressing tube on the proximal end side of the pressing tube; and a first locked portion configured to protrude from a lateral surface of the first arm portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application based on PCTInternational Application No. PCT/JP2014/061231, filed on Apr. 22, 2014,whose priority is claimed on U.S. Provisional Patent Application No.61/820,219, filed on May 7, 2013. The content of both the PCTInternational Application and the US Provisional Patent Application areincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a clip unit used to ligate a tissue.

Description of Related Art

Ligation devices including clip units have been used to ligate openingsformed in tissues or blood vessels. As such a clip unit, for example, anendoscope treatment tool disclosed in Japanese Unexamined PatentApplication, First Publication No. 2010-221059 has been known.

The clip unit disclosed in Japanese Unexamined Patent Application, FirstPublication No. 2010-221059 is configured to include a claw, a pressingtube, and a connection plate. The claw is a portion in which a halfwayportion is bent in an a shape and both ends thereof are formed in a clawshape. An arm portion of the claw is configured to be opened slightly byelastic resilience of the arm portion of the claw in a released naturalstate.

In the connection plate, a hole is provided in a hand-side end portionand a hook portion is formed in a distal-end-side end portion. The hookportion is hooked to a proximal-end-side loop portion of the claw so asto be disposed inside the pressing tube. At this time, the α portion ofthe claw is not drawn deeply into the pressing tube and the arm portionof the claw can be opened slightly.

The clip unit having the above-described configuration which isdisclosed in Japanese Unexamined Patent Application, First PublicationNo. 2010-221059, is introduced into the body cavity by using anendoscope ligation device. The endoscope ligation device includes anintroduction tube, a manipulation wire (linear member), a manipulationportion main body, and a slider. A coil sheath is inserted so as to beadvanceable and retractable inside the introduction tube. Themanipulation wire is inserted so as to be advanceable and retractableinside the coil sheath. The manipulation portion main body is attachedto the proximal end of the coil sheath. The slider is configured to beattached to the proximal end of the manipulation wire via a pipe and tobe slidable with the manipulation portion main body. The above-describedclip unit is attached to the distal end of the manipulation wire.

A halfway portion of the manipulation wire is turned back through thehole of the connection plate. Portions on both sides of the manipulationwire formed as two wires by turning back the halfway portion areinserted parallel to each other so as to be advanceable and retractableinside the coil sheath. The slider is fixed on the both proximal ends ofthe manipulation wire. The pipe is fitted to the both proximal ends ofthe manipulation wire.

The clip unit and the endoscope ligation tool having the above-describedconfiguration are used as follows.

The clip unit is accommodated inside the introduction tube. Theintroduction tube of the endoscope ligation device in this state isinserted into a channel of an endoscope which has been inserted into abody cavity in advance. After the distal end of the introduction tubereaches inside the body cavity, the introduction tube is pulled towardthe hand side to make the clip unit to protrude from the distal end ofthe introduction tube.

By pulling the slider toward the hand side with a light force, the αportion of the claw is drawn inside the pressing tube to open the clawmore widely. In this state, the introduction tube is pushed into theendoscope to press the opened claw against a target bleeding site or thelike inside a body cavity.

In this state, when the slider is strongly pulled toward the hand side,the proximal end of the arm portion is drawn to the pressing tube sothat the claw is closed and the tissue of the bleeding site is grasped.When the slider is pulled more strongly, the hook portion of theconnection plate is stretched so that the clip unit is separated fromthe endoscope ligation device and detained inside the body cavity whilethe clip unit grasping the tissue.

SUMMARY OF THE INVENTION

In one embodiment, a clip unit is provided, comprising: a clip main bodyhaving a first arm portion, a second arm portion, and a middle portiondisposed between a proximal end of the first arm portion and a proximalend of the second arm portion; a pressing tube formed in a tube shape tobe capable of accommodating the clip main body, the pressing tube beingprovided to deform the clip main body so as to make a distal end of thefirst arm portion and a distal end of the second arm portion approach toeach other, as the middle portion, the first arm portion, and the secondarm portion are moved toward a proximal end side of the pressing tube; alocking portion configured to protrude from an inner circumferentialsurface of the pressing tube on the proximal end side of the pressingtube; and a first locked portion configured to protrude from a lateralsurface of the first arm portion, the first locked portion beingmoveable both in a proximal direction and a distal direction withrespect to the pressing tube when the first locked portion is locatedmore distal than the locking portion inside the pressing tube, whereinmovement in the distal direction of the first locked portion withrespect to the pressing tube is restricted by engagement of the firstlocked portion and the locking portion after the first locked portionhas been moved beyond the locking portion to be located more proximalthan the locking portion.

In one example, the clip unit further comprises: a second locked portionconfigured to protrude from a lateral surface of the second arm portion,wherein, when the first locked portion approaches the second lockedportion as the first arm portion approaches the second arm portion byaction of the pressing tube, the first locked portion and the secondlocked portion are movable beyond the locking portion toward theproximal end side of the pressing tube.

In another example, the locking portion is provided at a proximal end ofthe pressing tube, and at least a part of the middle portion protrudespast the proximal end of the pressing tube when the first locked portionis moved beyond the locking portion.

In another example, the pressing tube is formed in a cylindrical shape,and the locking portion is formed over an entire inner circumferentialsurface of the pressing tube so that an edge of the locking portion isformed in a circular shape coaxial with the pressing tube.

In another example, the first locked portion includes a distal-end-sideend surface formed from a surface substantially orthogonal to alongitudinal axis of the clip main body and a proximal-end-side endsurface formed in a tapered shape, and an amount of power necessary topass the first locked portion through the locking portion from aproximal end side of the locking portion is greater than an amount ofpower necessary to pass the first locked portion through the lockingportion from the distal end side of the locking portion.

In another example, an elastic member is provided inside the pressingtube to bias the clip main body against the pressing tube in the distaldirection, and the clip main body is moved in the distal direction withrespect to the pressing tube by a bias force of the elastic member whenthe first locked portion is located more distal than the locking portioninside the pressing tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view (by cutting away a part of a side surface ofthe endoscope treatment tool) schematically showing an endoscopetreatment tool in which a clip unit according to an embodiment of thepresent invention is used.

FIG. 2 is a top sectional view schematically showing the distal end ofthe endoscope treatment tool in FIG. 1.

FIG. 3 is a side sectional view showing a clip unit in FIG. 1.

FIG. 4 is a side sectional view showing the proximal end of theendoscope treatment tool in FIG. 1.

FIG. 5 is a top sectional view showing the proximal end of the endoscopetreatment tool in FIG. 1.

FIG. 6 is a schematic perspective view taken along the cutting lineA1-A1 in FIG. 3.

FIG. 7 is a diagram schematically showing a state of the clip unit inFIG. 1 when viewed from the proximal end side.

FIG. 8 is a diagram taken along the cutting line A2-A2 in FIG. 4.

FIG. 9 is a top sectional view schematically showing a fracturemechanism of the endoscope treatment tool in FIG. 1.

FIG. 10 is a diagram taken along the cutting line A3-A3 in FIG. 9.

FIG. 11 is a schematic diagram showing a technique of using theendoscope treatment tool in FIG. 1.

FIG. 12 is a schematic diagram showing an amount of power necessary topull back a slider with respect to a movement amount by which the slideris pulled back in the endoscope treatment tool in FIG. 1.

FIG. 13 is a side sectional view schematically showing the endoscopetreatment tool when the clip unit in FIG. 1 is in a contact state.

FIG. 14 is a top sectional view schematically showing the endoscopetreatment tool when the clip unit in FIG. 1 is in the contact state.

FIG. 15 is a side sectional view schematically showing the endoscopetreatment tool when the clip unit in FIG. 1 is in an overpass state.

FIG. 16 is a top sectional view schematically showing the endoscopetreatment tool when the clip unit in FIG. 1 is in the overpass state.

FIG. 17 is a schematic diagram of the clip unit in FIG. 1 in theoverpass state when viewed from the proximal end side.

FIG. 18 is side sectional view schematically showing the endoscopetreatment tool when the clip unit in FIG. 1 is in a locking state.

FIG. 19 is top sectional view schematically showing the endoscopetreatment tool when the clip unit in FIG. 1 is in the locking state.

FIG. 20 is a schematic diagram showing the clip unit in FIG. 1 in thelocking state when viewed from the proximal end side.

FIG. 21 is a top sectional view schematically showing the fracturemechanism in a fracture state when a technique using the endoscopetreatment tool showing in FIG. 1 is performed.

FIG. 22 is a view along the cutting line A4-A4 in FIG. 21.

FIG. 23 is a schematic diagram showing the technique of using theendoscope treatment tool in FIG. 1.

FIG. 24 is a schematic diagram showing the technique of using theendoscope treatment tool in FIG. 1.

FIG. 25 is a schematic diagram showing the technique of using theendoscope treatment tool in FIG. 1.

FIG. 26 is a side sectional view schematically showing an initial stateof the clip unit according to the embodiment of the present invention.

FIG. 27 is a top sectional view schematically showing the initial stateof the clip unit according to the embodiment of the present invention.

FIG. 28 is a schematic diagram when the initial state of the clip unitaccording to the embodiment of the present invention is viewed from theproximal end side.

FIG. 29 is a side sectional view schematically showing the overpassstate of the clip unit according to the embodiment of the presentinvention.

FIG. 30 is a top sectional view schematically showing the overpass stateof the clip unit according to the embodiment of the present invention.

FIG. 31 is a schematic diagram showing the overpass state of the clipunit according to the embodiment of the present invention when viewedfrom the proximal end side.

FIG. 32 is a side sectional view schematically showing a locking stateof the clip unit according to the embodiment of the present invention.

FIG. 33 is a top sectional view schematically showing the locking stateof the clip unit according to the embodiment of the present invention.

FIG. 34 is a schematic diagram showing the locking state of the clipunit according to the embodiment of the present invention when viewedfrom the proximal end side.

FIG. 35 is a side sectional view schematically showing the distal end ofan endoscope treatment tool in which a clip unit is used according to amodified example of the present invention.

FIG. 36 is a diagram schematically showing the clip unit in FIG. 35 whenviewed from the proximal end side.

FIG. 37 is a sectional view schematically showing main portions of theclip unit according to an embodiment of a modified example of thepresent invention.

FIG. 38 is an explanatory diagram schematically showing a protective capattached to the distal end of an endoscope treatment tool in FIG. 37.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of a clip unit and an endoscope treatmenttool having the clip unit according to the present invention will bedescribed with reference to FIGS. 1 to 38. Throughout all of thedrawings, ratios of the thicknesses or dimensions of respectiveconstituent elements are appropriately adjusted for clarity.

As shown in FIGS. 1 and 2, a ligation device as an endoscope treatmenttool 1 includes a clip unit (hereinafter also abbreviated as a “clip”)10 and a treatment tool body 40. The clip 10 can be detachably mountedon a distal end of the treatment tool body 40. FIGS. 1 and 2 are topsectional views passing through an axial line C1 of a pressing tube 31to be described below.

FIG. 3 is a side sectional view showing the clip 10 of the endoscopetreatment tool 1. FIG. 4 is a side sectional view showing a proximal endof the endoscope treatment tool 1. FIG. 5 is a top sectional viewshowing the proximal end of the endoscope treatment tool 1. Hereinafter,configurations and operations will be described with reference to theschematic drawings and main portions will be described with reference tothe detailed drawings.

(Configuration: Arm Portions 12 and 13 of the Clip 10)

As shown in FIGS. 1 and 2, the clip 10 includes a clip main body 11, thepressing tube 31, and a helical spring (elastic member) 36. The pressingtube 31 is formed in a cylindrical shape and accommodates the proximalend of the clip main body 11. The helical spring 36 is accommodatedinside the pressing tube 31. The members forming the clip 10 in additionto the clip main body 11 are formed, for example, of a material such asa cobalt-chromium alloy, titanium, or stainless steel. The clip 10 isconfigured to be capable of being observed by MRI (Magnetic ResonanceImaging) radioscopy.

The clip main body 11 includes a first arm portion 12, a second armportion 13, and a middle portion 14. The first arm portion 12 and thesecond arm portion 13 are disposed to extend from the proximal end sideto the distal end side of the clip main body 11 and face each other. Themiddle portion 14 is disposed to be located between a proximal end ofthe first arm portion 12 and a proximal end of the second arm portion13.

The first arm portion 12 and the second arm portion 13 are formed to bemutually separated in a natural state from the proximal end side to thedistal end side. A claw 12 a extending toward a side of the second armportion 13 is formed at a distal end of the first arm portion 12.

In the first arm portion 12 and the second arm portion 13, across-sectional shape orthogonal to a longitudinal direction on thedistal end side thereof is formed as an arc-like round shape, as shownin FIG. 6. More specifically, a middle portion of the outside surface ofeach of the arm portions 12 and 13 in an orthogonal direction Z to bedescribed below is formed in a curved shape that is convex toward theoutside.

Thus, for the first arm portion 12 and the second arm portion 13, thestrength against bending is improved and frictional resistance to asheath tube 50 to be described below is reduced, so that advancement andretraction operations can smoothly be performed.

(Configuration: First Locked Portions 16 and 17 of Clip 10)

Here, as shown in FIG. 1, an axis X in which the first arm portion 12and the second arm portion 13 face each other, an axis Y parallel to anaxial line C1 of the pressing tube 31, and an axis Z orthogonal to eachof the axis X and the axis Y are defined. As shown in FIG. 2, two firstlocked portions 16 and 17 are provided at the proximal end of the firstarm portion 12. The first locked portions 16 and 17 are provided toprotrude from a lateral surface of the first arm portion 12 in the axisZ on a criterion plane S1 parallel to the axial line (central axialline) C1 of the pressing tube 31. The first locked portions 16 and 17protrude in opposite directions.

FIG. 2 is a diagram of the endoscope treatment tool in FIG. 1 whenviewed in a direction orthogonal to the criterion plane S1. In the topview shown in FIG. 2, the first locked portions 16 and 17 are formed tobe line-symmetric with respect to the axial line C1.

As shown in FIG. 2, a proximal end surface 16 a of the first lockedportion 16 is formed to be separated and inclined from the first armportion 12 (central axial line C1) toward the distal end side of thefirst locked portion 16. A distal end surface 16 b of the first lockedportion 16 is orthogonal to the axis Y. A proximal end surface 17 a anda distal end surface 17 b of the first locked portion 17 are formed tobe line-symmetric to the proximal end surface 16 a and the distal endsurface 16 b of the first locked portion 16 with respect to the axialline C1, respectively.

(Configuration: Protrusion Portions 18 and 19 of Clip 10)

As shown in FIGS. 1 and 2, two protrusion portions 18 and 19 areprovided more distal than the first locked portions 16 and 17 in thefirst arm portion 12. The protrusion portions 18 and 19 protrude fromthe lateral surface of the first arm portion 12 in the axis Z. Theprotrusion portions 18 and 19 are formed to be line-symmetric withrespect to the axial line C1 in a top view. Lengths of the protrusionportions 18 and 19 protruding from the first arm portion 12 in the axisZ are longer than the first locked portions 16 and 17 which protrudefrom the first arm portion 12 in the axis Z.

(Configuration: Arm Portion 13 of Clip 10)

As shown in FIG. 1, a claw 13 a extending toward the side of the firstarm portion 12 is formed at a distal end of the second arm portion 13.

In the second arm portion 13, second locked portions 21, 22 andprotrusion portions 23, 24 are formed like the first locked portions 16,17 and the protrusion portions 18, 19 of the first arm portion 12,respectively (the second locked portion 22 is referred to in FIG. 7 andthe protrusion portion 24 is not shown). That is, the second lockedportions 21 and 22 protrude from the lateral surface of the second armportion 13 in the axis Z. The protrusion portions 23 and 24 are providedto protrude from the lateral surface of the second arm portion 13 in theaxis Z more distal than the second locked portions 21 and 22 in thesecond arm portion 13. The second locked portions 21, 22 and theprotrusion portions 23, 24 are disposed to be parallel to the firstlocked portions 16, 17 and the protrusion portions 18, 19 in the axis X,respectively. That is, in FIG. 2, the first locked portions 16 and 17overlap the second locked portions 21 and 22 and the protrusion portions18 and 19 overlap the protrusion portions 23 and 24.

In a side view shown in FIG. 1, the first arm portion 12 and the secondarm portion 13 are formed at positions which are line-symmetric withrespect to the axial line C1.

For the clip main body 11, a plate formed for example, of acobalt-chromium alloy or the like is punched in a shape in which the armportions 12 and 13, the middle portion 14, the first locked portions 16and 17, the second locked portions 21 and 22, and the protrusionportions 18, 19, 23, and 24 are spread in a planar form. Then, thepunched member is integrally formed in a C shape in a side view bybending a connection portion of the first arm portion 12 and the middleportion 14 and a connection portion of the second arm portion 13 and themiddle portion 14.

(Configuration: Locking Portion 32 of Clip 10)

As shown in FIGS. 2 and 7, on the inner circumferential surface of theproximal end of the pressing tube 31, a locking portion 32 protrudesover the entire inner circumference surface. When viewed in thedirection of axis Y shown in FIG. 7, an edge 32 a of the locking portion32 on a side of the axial line C1 is formed in a circular shape that iscoaxial with the pressing tube 31. As shown in FIG. 2, a proximal endsurface 32 b (proximal-end-side end surface) and a distal end surface 32c (distal-end-side end surface) of the locking portion 32 are orthogonalto the axis Y.

Portions on the proximal end side of the protrusion portions 18 and 19in the first arm portion 12, portions on the proximal end side of theprotrusion portions 23 and 24 in the second arm portion 13, and themiddle portion 14 can be inserted into the locking portion 32. As shownin FIG. 7, a length L1 between an end of the first locked portion 16 andan end of the first locked portion 17 in the axis Z is less than theinner diameter of the locking portion 32. In an initial state to bedescribed below, parts of the first locked portions 16 and 17 are set tooverlap the locking portion 32 when viewed along the axis Y. That is, inthe state shown in FIG. 7, the edge 32 a is set such that the length L1of the first locked portions 16 and 17 is longer than a height (a lengthof a line segment between positions P1 and P2 in FIG. 7) of the edge 32a in which the first locked portions 16 and 17 face each other at thepositions P1 and P2.

As shown in FIG. 2, a tapered surface 31 a is formed over the entireinner circumference surface at the distal end of the pressing tube 31.The diameter of the tapered surface 31 a expands toward the distal endside of the pressing tube.

The pressing tube 31 and the locking portion 32 are integrally formed ofa material such as, for example, a 64 titanium alloy (Ti-6AL-4V) or acobalt-chromium alloy.

(Configuration: Helical Spring 36 of Clip 10)

As shown in FIG. 3, an end turn portion 36 b is provided at the distalend of the helical spring 36. The inner diameter of the formed end turnportion 36 b is less than that of the other portions of the helicalspring 36.

When the helical spring 36 is accommodated inside the pressing tube 31,the distal end thereof interlocks with the protrusion portions 18, 19,23, and 24 and the proximal end thereof interlocks with the lockingportion 32. The proximal end of the helical spring 36 and the lockingportion 32 may be fixed by welding or the like.

The portions on the proximal end side of the protrusion portions 18 and19 in the first arm portion 12, the portions on the proximal end side ofthe protrusion portions 23 and 24 in the second arm portion 13, and themiddle portion 14 can be inserted into the helical spring 36. When theprotrusion portions 18, 19, 23, and 24 are moved toward the proximal endside, the protrusion portions 18, 19, 23, and 24 interlock with the endturn portion 36 b of the helical spring 36. Even when the helical spring36 does not include the end turn portion 36 b, the same advantage can beobtained by using a separate member such as a washer at the distal endof the helical spring 36.

In the initial state of the clip 10 shown in FIGS. 1 and 2, the proximalend of the first arm portion 12, the proximal end of the second armportion 13, and the middle portion 14 are located at the distal end sidewith respect to the locking portion 32 inside the pressing tube 31. Thefirst locked portions 16 and 17 and the second locked portions 21 and 22do not come into contact with the locking portion 32 of the pressingtube 31. Wires 36 a of the helical spring 36 adjacent to each other inthe axis Y are separated from each other. The helical spring 36 iscompressed in the axis Y slightly more than in the natural state. Thedistal end of the first arm portion 12 and the distal end of the secondarm portion 13 of the clip main body 11 are separated from each other soas to be in an opened state.

(Configuration: Relation Between Clip Main Body 11 of Clip 10 andPressing Tube 31)

In the clip 10 with the above-described configuration, the first armportion 12 and the second arm portion 13 are separated in the axis X inthe initial state. Therefore, as shown in FIG. 7, when the first lockedportion 16 is viewed from the proximal end side, the first lockedportion 16 is overlapped by a portion of the edge 32 a at the positionP1 of the locking portion 32. That is, when first arm portion 12 ismoved toward the proximal end side with respect to the pressing tube 31,the first locked portion 16 comes into contact with the portion of theedge 32 a at the position P1. The portion of the edge 32 a at theposition P1 comes into point contact with the first locked portion 16.

Likewise, when the first arm portion 12 is moved toward the proximal endside with respect to the pressing tube 31, the first locked portion 17comes into contact with the portion of the edge 32 a at the position P2.A part of the edge 32 a at the position P2 comes into point contact withthe first locked portion 17. A proximal end surface 16 a of the firstlocked portion 16 comes into contact with the portion of the edge 32 aat the position P1. A proximal end surface 17 a of the first lockedportion 17 comes into contact with the portion thereof at the positionP2.

Positions of the edge 32 a corresponding to the positions P1 and P2 areindicated by positions Q1 and Q2 in FIG. 2.

When the second arm portion 13 integrally formed with the first armportion 12 is moved toward the proximal end side with respect to thepressing tube 31, the second locked portions 21 and 22 come into contactwith the locking portion 32 of the pressing tube 31, like the firstlocked portions 16 and 17 of the first arm portion 12.

(Configuration: Treatment Tool Body 40)

Next, the configuration of the treatment tool body 40 will be described.

As shown in FIGS. 1 and 2, the treatment tool body 40 includes thesheath tube 50, an insertion portion 60 and a manipulation portion 100.The insertion portion 60 is inserted inside the sheath tube 50 to beadvanceable and retractable. The manipulation portion 100 is attached tothe proximal end of the insertion portion 60.

The sheath tube 50 can be formed of, for example, a fluorine resin suchas polytetrafluoroethylene (PTFE) or a resin material such ashigh-density polyethylene (HDPE).

(Configuration: Sheath Portion 61 of Treatment Tool Body 40)

The insertion portion 60 includes a sheath portion 61, a manipulationwire 62, and a connection member 63. The manipulation wire 62 isinserted into the sheath portion 61 so as to be advanceable andretractable. The connection member 63 is connected to the distal end ofthe manipulation wire 62. The connection member 63 is provided to berotatable about an axis parallel to the axis X with respect to themanipulation wire 62.

The sheath portion 61 includes a coil sheath 66 and a distal end member(stopper portion) 67 fixed to the distal end of the coil sheath 66. Thecoil sheath 66 is formed, for example, of stainless steel with a highcompression resistance such as SUS301 of JIS (Japanese IndustrialStandards).

A coil formed by densely winding a wire (not shown) in the axis Y can beused as the coil sheath 66. The coil sheath 66 has flexibility and isstrong against a compressive force in the axis Y. The inner diameter ofthe coil sheath 66 is almost the same as the inner diameter of thehelical spring 36.

The distal end member 67 is formed of, for example, stainless steel in acylindrical shape. The inner diameter of the distal end member 67 isless than the inner diameter of the coil sheath 66. The outer diameterof the distal end member 67 is greater than that of the coil sheath 66or the pressing tube 31. A concave portion 67 a is formed on the outercircumferential surface of the proximal end of the distal end member 67by reducing the outer diameter thereof. When the distal end of the coilsheath 66 engages with the concave portion 67 a, the distal end member67 and the coil sheath 66 are fixed together by laser welding or thelike.

Thus, on the inner circumferential surface of the distal end of thesheath portion 61, a stepped portion 68 is formed in a connectionportion of the coil sheath 66 and the distal end member 67 by reducingthe inner diameter of the distal end member 67 provided more distal thanthe coil sheath 66 with respect to the coil sheath 66. The innerdiameter of the distal end member 67 is formed so that the distal endmember 67 does not engage with the first locked portions 16 and 17 andthe second locked portions 21 and 22 when the clip 10 engages with thelocking portion 32, as will be described below.

(Configuration: Distal End Member 67 of Treatment Tool Body 40)

A concave portion is formed over the entire inner circumferentialsurface of the distal end of the distal end member 67 and a supportmember 69 is disposed more distal than the concave portion. In thisexample, the support member 69 is formed in a cylindrical shape. Thesupport member 69 has an inner diameter that is slightly greater thanthe outer diameter of the pressing tube 31 and has dimensions such thatthe proximal end of the pressing tube 31 can be accommodated therein. Inthe concave portion on the inner circumferential surface of the supportmember 69, a surface facing forward is a distal end support surface(distal end surface) 67 b. The distal end support surface 67 b can comeinto contact with the proximal end surface of the pressing tube 31. Theclip 10 is disposed on the distal end side of the sheath portion 61. Thesupport member 69 can support the outer circumferential surface of thepressing tube 31 coming into contact with the distal end support surface67 b.

In this configuration, shaking of the clip 10 with respect to thesupport member 69 can be suppressed to be as small as possible, and thusan inclination of the clip 10 with respect to the support member 69 canbe allowed to some extent. Therefore, the endoscope treatment tool 1 canbe inserted smoothly even into the bending shape of an endoscope channelor the like.

(Configuration: Manipulation Wire 62 of Treatment Tool Body 40)

The manipulation wire 62 is formed of, for example, a single line modeof metal or a twisted line made of a metal. A loop portion 73 isprovided at the distal end of the manipulation wire 62 via a diameterexpansion portion 72. A linear member 74 (see FIG. 1) is formed by themanipulation wire 62 and the loop portion 73.

The diameter expansion portion 72 is formed of, for example, a metal orthe like in a cylindrical shape. The outer diameter of the diameterexpansion portion 72 is less than the inner diameter of the coil sheath66 and is greater than the inner diameter of the distal end member 67.When the distal end surface of the diameter expansion portion 72 comesinto contact with the stepped portion 68, the protrusion amount of theloop portion 73 with respect to the sheath portion 61 is regulated up toa length L2 (see FIG. 24). The length L2 is the maximum protrusionamount of the loop portion 73 allowed by the distal end member 67.

The loop portion 73 is formed by turning back a wire 73 a. The wire 73 ais turned back so that the turned portion is on the distal end side ofthe wire 73 a. Both ends of the wire 73 a are fixed to the diameterexpansion portion 72 by brazing, resistance welding, or the like.

(Configuration: Connection Member 63 of Treatment Tool Body 40)

The connection member 63 includes a hook portion 77 at the distal end ofa connection portion body 76, and a through hole 76 a is formed at theproximal end of the connection portion body 76. An inclination surface76 b is formed on a surface facing the hook portion 77 in the connectionportion body 76.

When the turned portion of the wire 73 a of the loop portion 73 isinserted into the through hole 76 a, the connection member 63 isconnected to the loop portion 73 to be rotatable about an axis parallelto the axis X (rotatable in an arrow direction D in FIG. 2).

The width of the connection member 63 is the outer diameter of theconnection portion body 76 in a direction orthogonal to the centralaxial line C1 when the hook portion 77 is disposed on the distal endside of the connection portion body 76. The width of the connectionmember 63 is slightly less than the inner diameter of the helical spring36, the inner diameter of the coil sheath 66, and the inner diameter ofthe distal end member 67. That is, the connection member 63 is notrotatable with respect to the loop portion 73 inside the pressing tube31 and inside the sheath portion 61 when the hook portion 77 is disposedon the distal end side of the connection portion body 76. In otherwords, relative movement of the clip main body 11 and the hook portion77 in a radial direction is regulated by the pressing tube 31 or thesheath portion 61.

The fact that “the connection member 63 is not rotatable with respect tothe loop portion 73” mentioned here means that the connection member 63is not rotatable with respect to the loop portion 73 until theengagement of the hook portion 77 and the middle portion 14 is released,as will be described below. Also, the fact that “the connection member63 is not rotatable with respect to the loop portion 73” does notliterally mean that the connection member 63 is completely not rotatablewith respect to the loop portion 73 even at a small angle.

By disposing the middle portion 14 between the hook portion 77 of theconnection member 63 and the inclination surface 76 b of the connectionmember 63, the hook portion 77 can engage with the middle portion 14.When the hook portion 77 is rotated with respect to the loop portion 73in the direction D (see FIG. 2), the engagement of the hook portion 77and the middle portion 14 is released. Thus, the connection member 63 isconnected to be detachably mounted on the clip main body 11. Theconnection member 63 is located inside the pressing tube 31.

(Configuration: Manipulation Portion 100 of Treatment Tool Body 40)

As shown in FIG. 1, the manipulation portion 100 includes a manipulationportion main body 101, a slider 102, and a fracture mechanism 64. Themanipulation portion main body 101 is installed on the proximal end ofthe coil sheath 66. The slider 102 is provided to be externally fittedto the manipulation portion main body 101 and to be slidable withrespect to the manipulation portion main body 101 in the axis Y. Thefracture mechanism 64 is connected to the proximal end of themanipulation wire 62 and the slider 102.

The manipulation portion main body 101 is formed in a rod shapeextending in the axis Y. A finger hooking portion 101 a is attached tothe proximal end of the manipulation portion main body 101. On theproximal end side of the finger hooking portion 101 a, a planar portion101 c is provided so that the manipulation portion 100 can be easilygrasped with two hands (see FIG. 4). A slit 101 b extending in the axisY is formed in the manipulation portion main body 101.

The slider 102 is formed in a cylindrical shape. On the outercircumferential surface of the slider 102, a concave portion 102 a isformed around the circumference. A pair of flange portions 102 b and 102c are formed in the slider 102 in the axis Y so that the concave portion102 a is located between a pair of flange portions 102 b and 102 c. Thepair of flange portions 102 b and 102 c have elliptical shapes whenviewed in the axis Y (see FIGS. 4 and 8). Thus, the slider 102 can beeasily grasped. When the manipulation portion 100 of the endoscopetreatment tool 1 is packed, space can be saved. As shown in FIG. 5, agroove 102 e extending in the axis Z is formed in a tube hole 102 d ofthe slider 102.

When the slider 102 engages with the slit 101 b of the manipulationportion main body 101, the movement range of the slider 102 with respectto the manipulation portion main body 101 in the axis Y is regulated.

(Configuration: Fracture Mechanism 64 of Treatment Tool Body 40)

The fracture mechanism 64 is disposed inside the tube hole 102 d of theslider 102, as shown in FIGS. 4 and 5. In other words, the fracturemechanism 64 is built in the manipulation portion 100.

As shown in FIGS. 9 and 10, the fracture mechanism 64 includes firstsupport members 80, second support members 81, a fracturable member 82,and elastic members 83. The first support member 80 is connected to theproximal end of the manipulation wire 62. The second support member 81is disposed on the proximal end side of the first support member 80. Thefracturable member 82 and the elastic member 83 are connected to thefirst support member 80 and the second support member 81.

In this example, the fracture mechanism 64 includes a pair of firstsupport members 80, a pair of second support members 81, and a pair ofelastic members 83. The pair of the first support members 80, the pairof the second support members 81, and the pair of the elastic members 83are disposed to be line-symmetric along the axial line C1 in a top viewshown in FIG. 9.

As shown in FIGS. 9 and 10, the first support member 80 includes asupport portion body 85 and a wall portion 86. The support portion body85 is formed in a plate shape extending in the axis Y. The wall portion86 is erected in a direction which is the axis Z from the distal end ofthe support portion body 85 and is a separation direction from the axialline C1. A groove 85 a extending in the axis Z is formed at the distalend of the surface of the support portion body 85 on the side of theaxial line C1. An accommodation portion 85 b is formed at the proximalend of the surface of the support portion body 85 on the side of theaxial line C1. The first support member 80 is formed of a material suchas, for example, a resin.

A wire fixing portion 62 a is fixed to the proximal end of themanipulation wire 62 and has a larger diameter than the manipulationwire 62. The wire fixing portion 62 a is formed integrally with themanipulation wire 62 and is interposed between both sides of the grooves85 a of the pair of the first support members 80 so as to engage withthe pair of the first support members 80. Thus, the pair of the firstsupport members 80 are connected to the proximal end of the manipulationwire 62.

(Configuration: Second Support Member 81 of Treatment Tool Body 40)

The second support members 81 are disposed to face the surfaces of thefirst support members 80 orthogonal to the axis Y. Specifically, thesecond support member 81 includes a support portion body 87 and a wallportion 88. The support portion body 87 is formed in a plate shapeextending in the axis Y. The wall portion 88 is erected in axis Z whichis orthogonal to the proximal end of the support portion body 87 and isa direction away from the axial line C1. An accommodation portion 87 ais formed at the distal end of the surface of the support portion body87 on the side of the axial line C1. A protrusion 88 b is formed on adistal end surface of the wall portion 88 in the erection direction (thedirection away from the axial line C1) in which the wall portion 88 iserected. The protrusion 88 b engages with the groove 102 e of the slider102. The proximal end surface 86 a of the wall portion 86 and the distalend surface 88 a of the wall portion 88 face each other in the axis Y.

(Configuration: Fracturable Member 82 of Treatment Tool Body 40)

The fracturable member 82 is formed of a metal such as, for examplestainless steel in a plate shape. The fracturable member 82 includes afirst end portion 89, a second end portion 90, and a middle fractureportion 91. The first end portion 89 is connected to the support portionbody 85 of the first support member 80. The second end portion 90 isconnected to the support portion body 87 of the second support member81. The middle fracture portion 91 is disposed between the first endportion 89 and the second end portion 90. The fracturable member 82 isconfigured such that the width of the middle fracture portion 91 isnarrower than the width of the first end portion 89 and than the widthof the second end portion 90.

A through hole 89 a is formed in the first end portion 89. By insertinga pin 92 provided in the accommodation portion 85 b of the supportportion body 85 through the through hole 89 a, the first end portion 89is connected to the first support member 80. A through hole 90 a isformed in the second end portion 90. By inserting a pin 93 provided inthe accommodation portion 87 a of the support portion body 87 throughthe through hole 90 a, the second end portion 90 is connected to thesecond support member 81. Gaps are formed between the pin 92 and thethrough hole 89 a and between the pin 93 and the through hole 90 a. Evenwhen the first support member 80 and the second support member 81 areconnected via the fracturable member 82, the proximal end surface of thesupport portion body 85 can be extruded toward the distal end side onthe distal end surface of the support portion body 87. Therefore, a loadcan be prevented from acting on the fracturable member 82 throughmanipulation of pushing of the manipulation wire 62 by the slider 102 tobe described below. As a result, in the fracturable member 82, thefracture strength of the fracturable member 82 can be prevented fromchanging due to occurrence of work hardening or brittle cracking.

The fracture strength to a pulling force in the axis Y is lower in themiddle fracture portion 91 than in the first end portion 89 and than inthe second end portion 90. The fracturable member 82 can be formedintegrally by performing press working on a metal plate.

(Configuration: Strength of Fracturable Member 82 of Treatment Tool Body40)

In the fracturable member 82, the middle fracture portion 91 is weakerthan the first support member 80 and the second support member 81. Thefracturable member 82 fractures due to the low fracture strength thereofin the axis Y. The force which fractures the fracturable member 82 ishigher (greater) than a force necessary to move the clip main body 11accommodated in the pressing tube 31 toward the proximal end side withrespect to the pressing tube 31 so as to make the clip main body 11 toenter an engagement state. Further, the fracture strength of thefracturable member 82 is lower than the fracture strength of the clipmain body 11, the connection member 63, the loop portion 73, thediameter expansion portion 72, and the manipulation wire 62. Inaddition, the fracture strength of the fracturable member 82 is lowerthan the connection strength between the clip main body 11 and theconnection member 63, between the connection member 63 and the loopportion 73, between the loop portion 73 and the diameter expansionportion 72, and between the diameter expansion portion 72 and themanipulation wire 62.

The fracture strength of the fracturable member 82 will be described asa specific numerical value. As will be described below, in one example,an amount of power (force) F1 necessary to move the locked portions 16,17, 21 and 22 from the distal side of the locking portion 32 to theproximal side of the locking portion 32 is in the range of about 20 N toabout 50 N. The fracture strength of the fracturable member 82 is set,for example, to about 100 N in consideration of a frictional force orthe like inside the insertion portion 60.

(Configuration: Elastic Member 83 of Treatment Tool Body 40)

In the embodiment, the elastic member 83 is configured by a helicalspring. The ends of the elastic member 83 are connected to the proximalend surface 86 a of the wall portion 86 and the distal end surface 88 aof the wall portion 88. The elastic member 83 is subjected to elasticdeformation rather than plastic deformation even when the fracturablemember 82 is drawn in the axis Y by the fracture strength of thefracturable member 82.

The support members 80 and 81 are disposed inside the tube hole 102 d ofthe slider 102, and thus the support members 80 and 81 are regulated tobe moved only in the axis Y with respect to the slider 102.

By engaging the protrusion 88 b of the second support member 81 with thegroove 102 e of the slider 102, the second support member 81 isconnected to the slider 102. The second support member 81 is integratedwith the slider 102 and is slid in the axis Y with respect to themanipulation portion main body 101. The first support member 80 isconnected to the second support member 81 via the fracturable member 82and the elastic member 83.

(Operation of Treatment Tool Body 40)

Next, an operation of the treatment tool body 40 will be described.

In the above-described configuration, the first support member 80, thesecond support member 81, and the fracturable member 82 can beintegrally moved toward the proximal end side. That is, when the secondsupport member 81 is pulled toward the proximal end side, thefracturable member 82 is moved toward the proximal end side, and thefirst support member 80 is accordingly moved toward the proximal endside.

The first support member 80 and the second support member 81 areconnected to the manipulation wire 62. Therefore, when the secondsupport member 81 is pulled toward the proximal end, the manipulationwire 62 is pulled toward the proximal end side. Hence, by pulling thesecond support member 81 toward the proximal end side, the clip mainbody 11 is pulled back with respect to the pressing tube 31, the clip 10is closed sequentially, and the locking portion 32 can finally lock thefirst locked portions 16 and 17 and the second locked portions 21 and22.

When a manipulation is performed to move the second support members 81toward the distal end side, the distal end surfaces of the supportportion bodies 87 of the second support members 81 come into contactwith the proximal end surfaces of the support portion bodies 85 of thefirst support members 80. Thus, when the second support members 81 aremanipulated toward the distal end side, the first support members 80 aremoved toward the distal end side and the manipulation wire 62 cantherefore be moved toward the distal end side.

The outer diameters of the pins 92 and 93 of the first support members80 and the second support members 81 are slightly less than the innerdiameters of the through holes 89 a and 90 a of the fracturable member82. Therefore, gaps are formed between the outer diameters of the pins92 and 93 and the inner diameters of the through holes 89 a and 90 a. Onthe other hand, the gaps provided between the first support members 80and the second support members 81 are configured to be less than theabove gaps. Accordingly, even when the second support members 81 aremoved toward the distal end side, the fracturable member 82 isconfigured so as not to move promptly toward the distal end side and acompressive force in the axis Y does not occur in the fracturable member82. Hence, deformation of the fracturable member 82 in which the amountof power for fracture is changed, such as work hardening by deformationof the fracturable member 82, does not occur.

In the above-described configuration, the clip main body 11 can be movedtoward the distal end side with respect to the pressing tube 31 when thesecond support members 81 are moved toward the distal end side. Bysliding the slider 102 in the axis Y with respect to the manipulationportion main body 101, the manipulation wire 62 can be manipulated to beadvanced and retracted in the axis Y.

(Action: Initial State)

Next, a technique used to ligate a target tissue with the clip 10 of theendoscope treatment tool 1 with the above-described configuration willbe described.

When the endoscope treatment tool 1 is provided to a user who is anoperator, as shown in FIG. 11, the sheath tube 50 is pushed to theinsertion portion 60 so that the clip 10 installed in the treatment toolbody 40 is hidden. The helical spring 36 of the clip 10 in the initialstate is compressed in the axis Y slightly more than in the naturalstate. Therefore, the proximal end surface of the pressing tube 31 comesinto contact with the distal end support surface 67 b. The distal endsurface of the diameter expansion portion 72 comes into contact with thestepped portion 68 and the loop portion 73 protrudes up to the maximumprotrusion amount from the distal end member 67.

Since the connection member 63 is disposed inside the pressing tube 31,the connection member 63 is not rotated with respect to the loop portion73 and the engagement of the hook portion 77 and the middle portion 14is maintained. At this time, the fracturable member 82 of the fracturemechanism 64 does not fracture.

When the endoscope treatment tool 1 is used, an endoscope insertionportion of an endoscope (not shown) is inserted into the body of apatient. The sheath tube 50 of the endoscope treatment tool 1 isinserted from the proximal end of a channel of the endoscope and thesheath tube 50 protrudes from the distal end of the channel of theendoscope. When the sheath tube 50 is pulled back with respect to theinsertion portion 60, the clip 10 protrudes from the distal end side ofthe sheath tube 50, as shown in FIG. 1. Thus, the arm portions 12 and 13of the clip 10 enter an opened state shown in FIG. 1.

FIG. 12 is a schematic diagram showing the amount of power necessary topull back the slider with respect to the movement amount by which theslider is pulled back in the endoscope treatment tool. The slider 102 ismoved (pulled back) toward the proximal end side with respect to themanipulation portion main body 101 from the initial state shown inFIG. 1. The clip 10 is configured such that the amount of powernecessary to pull back the slider 102 changes with this movement, asshown in FIG. 12. In FIG. 12, a relative change in the amount of powernecessary to pull back the slider in various states such as the initialstate of the clip 10 are shown.

The state of the clip 10 is changed from the initial state to a contactstate to an overpass state and then to a locking state as an operationof pulling back the slider 102. Hereinafter, the change in the amount ofpower and the change in the state of the clip 10 will be described indetail.

In the initial state, for example, the diameter expansion portion 72comes into contact with the stepped portion 68 even when the slider 102is erroneously moved (pushed) toward the distal end side with respect tothe manipulation portion main body 101. Therefore, the proximal endsurface of the pressing tube 31 comes into contact with the distal endsupport surface 67 b, and the pressing tube 31 and the distal endsupport surface 67 b are not separated over at least the depth of thesupport member 69 in the longitudinal direction.

Next, the clip 10 is turned toward the target tissue T (referred to FIG.15) inside the body by performing a manipulation of curving a curvingportion provided in the endoscope insertion portion while the inside ofthe body is examined with the endoscope. By pushing the endoscopetreatment tool 1 in the endoscope, the arm portions 12 and 13 arepressed against the target tissue T.

When the user grasps the manipulation portion 100 and pulls back theslider 102, the first arm portion 12 and the second arm portion 13 areurged toward the inner circumferential surface of the distal end of thepressing tube 31. As a result, the first arm portion 12 is elasticallydeformed on the side of the second arm portion 13 and the second armportion 13 is elastically deformed on the side of the first arm portion12, and thus the distal end of the first arm portion 12 approaches thedistal end of the second arm portion 13 (the arm portions 12 and 13 areclosed). The helical spring 36 is gradually compressed in the axis Y.

The amount of power by which the slider 102 is pulled back istransmitted to the fracturable member 82 via the second support member81. Since small gaps are merely present between the pin 92 and thethrough hole 89 a and between the pin 93 and the through hole 90 a, theamount of power by which the slider 102 is pulled back is received bythe fracturable member 82 rather than the elastic member 83.

(Action: Contact State from Initial State)

When the slider 102 is pulled further back, as shown in FIGS. 7, 13, and14, the first locked portions 16 and 17 and the second locked portions21 and 22 enter the contact state with the locking portion 32 of thepressing tube 31. At this time, as shown in FIG. 7, the first lockedportion 16 and the first locked portion 17 come into contact with theedge 32 a of the pressing tube 31 at the position P1 and the positionP2, respectively.

In a region R1 corresponding to the initial state to the contact state,as shown in FIG. 12, the amount of power necessary to pull back theslider 102 increases as the slider 102 is pulled back. The clip 10 ischanged from the opened state to the closed state. Since the connectionmember 63 is disposed inside the pressing tube 31 or the sheath portion61, the connection member 63 is not rotated with respect to the loopportion 73 and the engagement of the hook portion 77 and the middleportion 14 is maintained. Since the fracturable member 82 of thefracture mechanism 64 does not fracture, the amount of power by whichthe slider 102 is pulled back can be transmitted to the manipulationwire 62 via the fracturable member 82.

When the slider 102 is pushed, the proximal end surface of the supportportion body 85 is pushed toward the distal end side by the distal endsurface of the support portion body 87 of the fracture mechanism 64, sothat the amount of power by which the slider 102 is pushed can betransmitted to the manipulation wire 62.

(Action: Overpass State from Contact State)

Proximal end surfaces 16 a and 17 a of the first locked portions 16 and17 are formed to be inclined, as described above. The edge 32 a of thelocking portion 32 has a circular shape. Therefore, when the slider 102is pulled further back, the first locked portion 16 receives aperpendicular force from the edge 32 a in parallel to a normal line Northogonal to a tangent line θ of the edge 32 a at the position P1 atwhich the first locked portion 16 comes into contact with the edge 32 aof the locking portion 32, when viewed in the axis Y shown in FIG. 17.The perpendicular force moves the first locked portion 16 of the firstarm portion 12 in the axis X so that the first locked portion 16 becomescloser to the second arm portion 13.

When the pullback manipulation continues, as shown in FIGS. 15 to 17,the first locked portions 16 and 17 come into point contact with thelocking portion 32 and the edge 32 a of the locking portion 32 withwhich the first locked portion 16 comes into contact moves from theposition P1 to a position P3. Simultaneously, the edge 32 a of thelocking portion 32 with which the first locked portion 17 comes intocontact moves from the position P2 to a position P4. FIGS. 15 to 17illustrate the overpass state in which the distal end of the proximalend surface 16 a of the first locked portion 16 and the distal end ofthe proximal end surface 17 a of the first locked portion 17 come intocontact with the edge 32 a of the locking portion 32.

Likewise, the second arm portion 13 receives the perpendicular forcefrom the edge 32 a of the locking portion 32 and moves in the axis X tobecome closer to the first arm portion 12. At this time, the middleportion 14 is elastically deformed so that both ends of the middleportion 14 move toward the side of the axial line C1.

By rotating the manipulation wire 62 with respect to the sheath portion61 in the initial state, the direction of the clip 10 can be adjusted.At this time, the clip main body 11 is considered to be rotated aboutthe axial line C1 with respect to the pressing tube 31. However, sincethe edge 32 a of the locking portion 32 is formed in the circular shapecoaxial with the pressing tube 31, the locking state of the lockingportion 32, the first locked portions 16 and 17, and the second lockedportions 21 and 22 is maintained satisfactorily.

In a region R2 corresponding to the contact state to the overpass state,as shown in FIG. 12, there is an increase in the rate of the amount ofpower necessary to pull back the slider 102 per unit movement amount bywhich the slider 102 is pulled back (that is, the rate of increase isgreater than in the above-described region R1). In other words, whilethe change of the amount of power characteristic in which the gradient(slope) is relatively gentle is shown in the region R1, a change of theamount of power characteristic in which the gradient (slope) isrelatively sharp is shown in the region R2 in which the first lockedportions 16 and 17 and the second locked portions 21 and 22 come intocontact with the locking portion 32.

That is, the user who pulls back the slider 102 feels that the slider102 is abruptly heavier in the region R2 than in the region R1 when theuser pulls back the slider 102. Thus, the user can easily recognizewhether a state in which the user is currently pulling back the slider102 is in the region R1 or the region R2, in other words, the user caneasily recognize whether the slider 102 is being pulled beyond thecontact state.

In the region R2, the closed state of the clip 10 is maintained. Sincethe connection member 63 is disposed inside the sheath portion 61, theengagement of the hook portion 77 and the middle portion 14 ismaintained. The fracturable member 82 of the fracture mechanism 64 doesnot fracture. For example, an amount of power F1 necessary to cause theclip 10 to enter the overpass state, as shown in FIG. 12, is in therange of about 20 N to about 50 N (newtons).

As shown in FIG. 17, in the overpass state, a distance between thepositions P3 and P4 of the edge 32 a is the same as the length L1 of thefirst locked portions 16 and 17 described above.

(Action: Re-Gripping)

The clip 10 is elastically deformed. Therefore, when the slider 102 ispushed while the clip 10 is in any state in the regions R1 and R2, thecompressed helical spring 36 is stretched. When the pressing tube 31comes into contact with the distal end support surface 67 b, the clipmain body 11 is moved toward the distal end side with respect to thepressing tube 31 and the clip 10 enters the initial state shown inFIG. 1. For example, through the manipulation of the curving of thecurving portion, the clip 10 is turned toward another target tissue T.Thereafter, by performing the steps in the above-described order, thetarget tissue T can be re-gripped with the clip 10.

(Action: Locking State from Overpass State)

When the slider 102 is pulled further back from the overpass state, thepositions of the first arm portion 12 and the second arm portion 13 withrespect to the pressing tube 31 in the axis X and the axis Z aremaintained. In this state, the first arm portion 12 provided with thefirst locked portions 16 and 17 and the second arm portion 13 providedwith the second locked portions 21 and 22 are inserted inside thelocking portion 32. Then, the first locked portions 16 and 17 and thesecond locked portions 21 and 22 are moved toward the proximal end sidebeyond the locking portion 32.

At this time, the arm portions 12 and 13 and the middle portion 14 arenot urged from the locking portion 32. Therefore, as shown in FIGS. 18to 20, the proximal end side of the first arm portion 12 and theproximal end side of the second arm portion 13 are moved in the axis Xby the elastic force of the middle portion 14 to be separated from eachother. When a force for moving the clip main body 11 toward the proximalend side of the pressing tube 31 is released, the distal end surfaces 16b and 17 b of the first locked portions 16 and 17 enter the lockingstate in which the distal end surfaces 16 b and 17 b are locked by theproximal end surface 32 b of the locking portion 32 (that is, distal endsurfaces 16 b and 17 b are held distally relative to the proximal endsurface 32 b).

In a region R3 corresponding to the overpass state to the locking state,as shown in FIG. 12, a part of the elastic deformation of the armportions 12 and 13 and the middle portion 14 is released. Thus, theamount of power necessary to pull back the slider 102 graduallydecreases as the slider 102 is pulled back. In the region R3, the closedstate of the clip 10 is maintained. Since the connection member 63 isdisposed inside the sheath portion 61, the engagement of the hookportion 77 and the middle portion 14 is maintained. The fracturablemember 82 of the fracture mechanism 64 does not fracture.

When the clip 10 enters the locking state, as shown in FIGS. 18 and 19,the wires 36 a of the helical spring 36 compressed in the axis Y enter aclose coiling state in which the wires 36 a adjacent in the axis Y arealmost touching. When the clip 10 enters the locking state, the distalend surfaces 16 b and 17 b of the first locked portions 16 and 17interlock with the proximal end surface 32 b of the locking portion 32.Therefore, the movement of the clip main body 11 with respect to thepressing tube 31 toward the distal end side is regulated. That is, astate in which the clip 10 ligates the target tissue T is maintained andthe state of the clip does not return to the initial state in which thearm portions 12 and 13 enter the opened state. The clip 10 is fixed inthe state in which the arm portions 12 and 13 are closed. In the clip10, the middle portion 14 protrudes on the proximal end side withrespect to the pressing tube 31.

When the first locked portions 16 and 17 and the second locked portions21 and 22 are moved toward the proximal end side beyond the lockingportion 32, the first locked portions 16 and 17 and the second lockedportions 21 and 22 may pass over the locking portion 32 by scrapingagainst the locking portion 32 or deforming the locking portion 32. Inthis case, in order to prevent excessive breakage of the locking portion32, it is desirable to perform a chamfering process or the like onportions in which the first locked portions 16 and 17 and the secondlocked portions 21 and 22 come into contact with the locking portion 32.

(Action: Immediately Before Fracture State)

Since the helical spring 36 is in the compressed state, the clip mainbody 11 may not be moved toward the proximal end side with respect tothe pressing tube 31 even if the slider 102 is pulled further back. Thelocking state of the clip 10 is maintained and not changed. However,when the slider 102 is pulled back, a tensile force acting on thefracturable member 82, the manipulation wire 62, or the like graduallyincreases. In a region R4 shown in FIG. 12, i.e., the region R4corresponding to the locking state to a state immediately before afracture state of the fracture mechanism 64 to be described below, asshown in FIG. 12, the closed state of the clip 10 is maintained. Sincethe connection member 63 is disposed inside the sheath portion 61, theengagement of the hook portion 77 and the middle portion 14 ismaintained. The fracturable member 82 of the fracture mechanism 64 doesnot fracture.

(Action: Fracture State)

The slider 102 is pulled further back, a manipulation amount of power ofthe slider 102 reaches a value equal to or greater than a predeterminedvalue, and the tensile force acting on the fracturable member 82 exceedsthe fracture strength of the fracturable member 82. At this time, asshown in FIGS. 21 and 22, the middle fracture portion 91 of thefracturable member 82 in the fracture mechanism 64 fractures and themiddle fracture portion 91 is separated into fracture pieces 91 a and 91b. Thus, the fracture mechanism 64 enters the fracture state in whichthe fracturable member 82 fractures.

Due to a fracture impact, the fracture piece 91 a and the first supportmember 80 each attempt to fly out toward the distal end side. However,the movement toward the distal end side is regulated since the firstsupport member 80 and the second support member 81 are connected by theelastic member 83. The clip 10 does not deviate from the support member69. After the fracturable member 82 fractures, the connection statebetween the first support member 80 and the second support member 81 ismaintained by the elastic member 83.

The fracture impact of the middle fracture portion 91 is transmitted tothe user grasping the manipulation portion 100. That is, the fracturemechanism 64 causes the user to recognize that the clip 10 is fixed inthe closed state when the fracturable member 82 fractures. Since thefracture mechanism 64 is provided in the manipulation portion 100, theuser can more reliably recognize this impact.

When the user feels the transmitted impact, the user can recognize thatthe clip 10 has entered the locking state and the ligation state of thetarget tissue T is maintained. Even when the user pulls the slider 102further back and brings the slider 102 into contact with the proximalend of the slit 101 b of the manipulation portion main body 101, theuser can recognize that the clip 10 has entered the locking state.

The first support member 80 and the second support member 81 areconnected by the elastic member 83. Therefore, when the slider 102 ispulled further back, the elastic member 83 is stretched. Since the clip10 is in the locking state, the manipulation wire 62 is not moved towardthe proximal end side.

A region R5 shown in FIG. 12 includes the fracture state and a state inwhich the slider 102 is pulled further back than the clip is in thefracture state. In the region R5 shown in FIG. 12, the fracturablemember 82 fractures and then the elastic member 83 is stretched, andthus the amount of power necessary to pull back the slider 102temporarily decreases and then increases as the slider 102 is pulledback. In the region R5, the closed state of the clip 10 is maintained.Since the connection member 63 is disposed inside the sheath portion 61,the engagement of the hook portion 77 and the middle portion 14 ismaintained. The fracturable member 82 of the fracture mechanism 64fractures.

(Action: Separation of Clip 10)

Thereafter, the clip 10 is separated from the treatment tool body 40.

The order in which the clip 10 is separated from the treatment tool body40 is specifically as follows. That is, when the slider 102 is pushed,as shown in FIG. 23, the proximal end surface of the first supportmember 80 is pushed by the distal end surface of the second supportmember 81 and the manipulation wire 62 is moved toward the distal endside with respect to the coil sheath 66. As shown in FIG. 24, the distalend surface of the diameter expansion portion 72 comes into contact withthe stepped portion 68 and the loop portion 73 protrudes up to thelength L2 which is the maximum protrusion amount with respect to thedistal end member 67.

When the connection member 63 protrudes on the distal end side withrespect to the distal end member 67, the clip main body 11 and thepressing tube 31 are integrally moved toward the distal end side. Sincethe connection member 63 is located out of the pressing tube 31, theconnection member 63 can be rotated with respect to the loop portion 73.When the slider 102 is pushed and the manipulation wire 62 is movedtoward the distal end side, the inclination surface 76 b of theconnection member 63 comes into contact with the proximal end surface ofthe middle portion 14 of the clip 10 ligating the target tissue T. Asshown in FIG. 25, the hook portion 77 is guided to the inclinationsurface 76 b and is rotated in the direction D along with the connectionportion body 76, and thus the engagement of the hook portion 77 and themiddle portion 14 is released. Thus, the clip 10 ligating the targettissue T is maintained inside the body.

That is, the closed state of the clip 10 is maintained between the stateindicated by the region R5 and a state in which the slider 102 is pushedand the connection member 63 protrudes toward the distal end side withrespect to the distal end member 67, as shown in FIG. 24. The engagementof the hook portion 77 and the middle portion 14 can be released. Thefracturable member 82 of the fracture mechanism 64 has been fractured.

(Action: Final Treatment of Technique)

The slider 102 is pulled back and the connection member 63 isaccommodated inside the sheath portion 61.

The endoscope treatment tool 1 is extracted from the channel of theendoscope. The endoscope insertion portion of the endoscope is extractedfrom the body of the patient. Thereafter, any other necessary treatmentis performed and a series of operations of the technique ends.

(Action: Clip 10)

A technique of using the endoscope treatment tool 1 will be describedagain focusing on an action of the clip 10.

In the initial state of the clip 10 shown in FIGS. 26 to 28, the armportions 12 and 13 of the clip 10 are in the opened state. In theinitial state, the first locked portions 16 and 17 and the second lockedportions 21 and 22 do not come in contact with the locking portion 32 ofthe pressing tube 31.

When the clip main body 11 is moved toward the proximal end side withrespect to the pressing tube 31 from the initial state, the arm portions12 and 13 are pressed to the pressing tube 31, so that the clip entersthe closed state. Next, the clip enters the contact state in which thefirst locked portions 16 and 17 and the second locked portions 21 and 22come into contact with the locking portion 32 of the pressing tube 31(see FIGS. 7, 13, and 14). In the contact state, the closed state of thearm portions 12 and 13 is maintained. The helical spring 36 iscompressed in the axis Y.

When the clip main body 11 is further moved toward the proximal end sidefrom the contact state, the first locked portions 16 and 17 and thesecond locked portions 21 and 22 come into point contact with thelocking portion 32 and receive the perpendicular force. As a result, thearm portions 12 and 13 are elastically deformed in the axis X to becloser to each other. As shown in FIGS. 29 to 31, the clip enters theoverpass state in which the first locked portions 16 and 17 and thesecond locked portions 21 and 22 are inserted into the locking portion32. In the overpass state, the closed state of the arm portions 12 and13 is maintained.

When the clip main body 11 is further moved toward the proximal end sidefrom the overpass state, the first locked portions 16 and 17 and thesecond locked portions 21 and 22 are moved toward the proximal end sidebeyond the locking portion 32. The arm portions 12 and 13 areelastically deformed in the axis X to be mutually separated by theelastic force of the arm portions 12 and 13. Thus, as shown in FIGS. 32to 34, the clip enters the locking state in which the first lockedportions 16 and 17 and the second locked portions 21 and 22 interlockwith the locking portion 32 on the distal end side of the lockingportion 32. In the locking state, the closed state of the arm portions12 and 13 is maintained and the clip 10 does not return to any of thestates from the initial state to the overpass state.

(Advantages)

In the clip 10 according to the embodiment, the helical spring 36locking with the protrusion portions 18, 19, 23, and 24 of the clip mainbody 11 and the locking portion 32 of the pressing tube 31 is compressedin the axis Y. When the target tissue T is grasped between the armportions 12 and 13, the state in which the target tissue T is ligatedwith the arm portions 12 and 13 can be maintained.

Before the clip 10 in the initial state enters the locking state, theclip main body 11 is manipulated by the manipulation wire 62 to bepushed in a distal direction with respect to the pressing tube 31 and ismoved toward the distal end side. Thus, the helical spring 36 which hadbeen compressed in the axis Y is stretched. Accordingly, the clip mainbody 11 is moved toward the distal end side with respect to the pressingtube 31 and the clip 10 is returned to the initial state when thepressing tube 31 comes into contact with the distal end support surface67 b. By disposing the target tissue T between the arm portions 12 and13 and moving the arm portions 12 and 13 toward the proximal end sidewith respect to the pressing tube 31, the target tissue T can be easilyre-gripped.

In the embodiment, the target tissue T can be re-gripped with the clip10. Therefore, as shown in FIG. 12, the state of the clip 10 isconfigured to be classified into the regions R1 and R2 in which the clipis capable of returning to the initial state again even when the armportions 12 and 13 are closed and the region R3 in which the clip doesnot return to the initial state again. To distinguish the region R2 fromthe region R3, the locking portion 32, and the first locked portions 16and 17 and the second locked portions 21 and 22 are provided and thechange in the amount of power necessary to pull back the slider 102 isvaried with respect to the movement amount by which the slider 102 ispulled back.

As shown in FIG. 28, the second locked portions 21 and 22 are providedin the second arm portion 13. The second locked portions 21 and 22 aredisposed to be arranged with the first locked portions 16 and 17 in theaxis X. Thus, a force applied to the locking portion 32 will act moreequally in the circumferential direction of the pressing tube 31 so thatthe clip main body 11 can lock together with the locking portion 32 morereliably.

The first locked portions 16 and 17 protrude in the axis Z. When a platematerial is bent to form the clip main body 11, the first lockedportions 16 and 17 can be easily formed while the manufacturing cost isreduced.

When viewed in the axis X orthogonal to the criterion plane S1, theproximal end surface 16 a of the first locked portion 16 is inclined soas to be separated from the first arm portion 12 toward the distal endside. Further, the distal end surface 16 b of the first locked portion16 and the proximal end surface 32 b of the locking portion 32 areorthogonal to the axis Y. Accordingly, when the first arm portion 12 ismoved toward the proximal end side with respect to the pressing tube 31,the first arm portion 12 can be guided to smoothly approach the secondarm portion 13. On the other hand, when the distal end surface 16 b ofthe first locked portion 16 moved toward the proximal end side beyondthe locking portion 32 comes into contact with the proximal end surface32 b of the locking portion 32, the first locked portion 16 can reliablyinterlock with the locking portion 32 on the distal end side.

(Modified Examples)

Hereinafter, modified examples of the foregoing embodiment will bedescribed. In the foregoing embodiment, the first locked portions 16 and17 provided in the first arm portion 12 and the second locked portions21 and 22 provided in the second arm portion 13 are configured toprotrude in the axis Z. The axis Z is a separation direction from thesecond arm portion 13. However, as in a clip 10A shown in FIGS. 35 and36, a locked portion 111 may be provided to protrude from the sidesurface of the first arm portion 12 in the separation direction from thesecond arm portion 13 in the axis X. The locked portion 111 is formed toprotrude in the separation direction from the second arm portion 13 on acriterion plane S2 parallel to the axial line C1 of the pressing tube31. As shown in FIG. 35, when viewed from the axis Z orthogonal to thecriterion plane S2, a proximal end surface 111 a of the locked portion111 is inclined to be separate from the first arm portion 12 toward thedistal end side. A distal end surface 111 b of the locked portion 111 isorthogonal to the axis Y.

In this modified example, a locked portion 112 is provided to protrudefrom the side surface of the second arm portion 13 in a separationdirection from the first arm portion 12 in the axis X.

When viewed in the axis Z shown in FIG. 35, a proximal end surface 112 aand a distal end surface 112 b of the locked portion 112 are formed tobe line-symmetric with the proximal end surface 111 a and the distal endsurface 111 b of the locked portion 111 with respect to the axial lineC1.

Even when the locked portions 111 and 112 are configured in this way,the same advantages as those of the foregoing embodiment can beobtained.

The embodiment of the present invention has been described in detailabove with reference to the drawings, but the specific configuration isnot limited to the embodiment. Changes and the like in the configurationare included within the scope of the present invention without departingfrom the gist of the present invention.

For example, in the foregoing embodiment, the pressing tube 31 is formedin the cylindrical shape. That is, the cross-sectional surfaceorthogonal to the axial line C1 of the pressing tube 31 is a shape witha circular contour. However, the cross-sectional surface of the pressingtube is not limited thereto, but may be a shape with, for example, anelliptical contour, a polygonal contour, or the like.

The second locked portions 21 and 22 may not be formed in the second armportion 13. This is because the locking with the locking portion 32 onthe distal end side can be realized when the first locked portions 16and 17 are formed in the first arm portion 12. Further, in the first armportion 12, the first locked portion 17 may not be formed and only thefirst locked portion 16 may be formed.

The clip 10 may not include the helical spring 36. In the embodiment,the helical spring 36 has been configured to extrude the clip main body11 setting the pressing tube 31 as a base point. Also, the elastic forceof the clip main body 11 in an opening direction may be configured toadvance with respect to the pressing tube 31 by interaction with thedistal end of the pressing tube 31.

The protrusion portions 18 and 19 have been provided in the first armportion 12 and the protrusion portions 23 and 24 have been provided inthe second arm portion 13. However, the protrusion portions may beprovided in only one of the first arm portion 12 and the second armportion 13 and the number of protrusion portion provided in the one armportion may be one.

The protrusion portions 18 and 19 have been configured to protrude inthe axis Z, but may protrude in a direction intersecting the axis Y.Even in this configuration, the distal end of the helical spring 36 caninterlock with the protrusion portions.

In the foregoing embodiment, the distal end surface 16 b of the firstlocked portion 16 and the proximal end surface 32 b of the lockingportion 32 are orthogonal to the axis Y. As shown in FIG. 37, however,the distal end surface 16 b may be inclined to be separate from thefirst arm portion 12 toward the distal end side. The proximal endsurface 32 b may be inclined to be close to the axial line C1 of thepressing tube 31 toward the proximal end side.

In the foregoing embodiment, when viewed in the axis Y, the edge 32 a ofthe locking portion 32 is formed in the circular shape coaxial with thepressing tube 31. However, the shape of the edge 32 a may be, forexample, a shape with an elliptical contour, a polygonal contour, or thelike.

In the foregoing embodiment, a configuration is described that when theclip 10 is in the locking state, the helical spring 36 enters the closecoiling state, and thus the clip main body 11 has been provided not tomove toward the proximal end side with respect to the pressing tube 31.However, instead of the close coiling state of the helical spring 36,the clip main body 11 may be configured not to move toward the proximalend side with respect to the pressing tube 31 by locking together theprotrusions provided in the arm portions 12 and 13 and the lockingportion 32.

As shown in FIG. 38, when provided to the user, a protective cap 120 maybe installed to be detachably mounted on the distal end of the sheathtube 50 of the endoscope treatment tool 1. The protective cap 120 isformed in a tube shape and a butting portion 121 with a reduced innerdiameter is formed at the distal end thereof.

While embodiments of the invention have been described and illustratedabove, it should be understood that these are examples of the inventionand are not to be considered as limiting. Additions, omissions,substitutions, and other modifications can be made without departingfrom the spirit and scope of the present invention. Accordingly, theinvention is not to be considered as being limited by the foregoingdescription, and is only limited by the scope of the appended claims.

What is claimed is:
 1. A clip unit comprising: a clip main body having afirst arm portion, a second arm portion, and a middle portion disposedbetween a proximal end of the first arm portion and a proximal end ofthe second arm portion; a pressing tube formed in a tube shape to becapable of accommodating the clip main body, the pressing tube beingprovided to deform the clip main body so as to make a distal end of thefirst arm portion and a distal end of the second arm portion approach toeach other, as the middle portion, the first arm portion, and the secondarm portion are moved toward a proximal end side of the pressing tube; alocking portion configured to protrude from an inner circumferentialsurface of the pressing tube on the proximal end side of the pressingtube; and a first locked portion configured to protrude from a lateralsurface of the first arm portion, the first locked portion beingmoveable both in a proximal direction and a distal direction withrespect to the pressing tube when the first locked portion is locatedmore distal than the locking portion inside the pressing tube, whereinan opened state of the clip unit is defined as a state in which thedistal end of the first arm portion and the distal end of the second armportion are spaced from each other, and a closed state of the clip unitis defined as a state in which the first arm portion and the second armportion are deformed to approached each other, wherein the clip mainbody is configured to be moved proximally with respect to the pressingtube to deform the first arm portion and the second arm portion suchthat the clip unit is changed from the opened state to the closed state,and the clip main body is configured to be moved distally with respectto the pressing tube to deform the first arm portion and the second armportion such that the clip unit is changed from the closed state to theopened state, when the first locked portion is located more distallythan the locking portion, and wherein an advancement of the clip mainbody with respect to the pressing tube is restricted by an engagement ofthe first locked portion and the locking portion such that the closedstate is maintained, when the first locked portion is located moreproximally than the locking portion.
 2. The clip unit according to claim1, further comprising: a second locked portion configured to protrudefrom a lateral surface of the second arm portion, wherein, when thefirst locked portion approaches the second locked portion as the firstarm portion approaches the second arm portion by action of the pressingtube, the first locked portion and the second locked portion are movablebeyond the locking portion toward the proximal end side of the pressingtube.
 3. The clip unit according to claim 2, wherein the locking portionis provided at a proximal end of the pressing tube, and at least a partof the middle portion protrudes past the proximal end of the pressingtube when the first locked portion is moved beyond the locking portion.4. The clip unit according to claim 3, wherein the pressing tube isformed in a cylindrical shape, and the locking portion is formed over anentire inner circumferential surface of the pressing tube so that anedge of the locking portion is formed in a circular shape coaxial withthe pressing tube.
 5. The clip unit according to claim 4, wherein thefirst locked portion includes a distal-end-side end surface formed froma surface substantially orthogonal to a longitudinal axis of the clipmain body and a proximal-end-side end surface formed in a tapered shape,and an amount of power necessary to pass the first locked portionthrough the locking portion from a proximal end side of the lockingportion is greater than an amount of power necessary to pass the firstlocked portion through the locking portion from a distal end side of thelocking portion.
 6. The clip unit according to claim 5, wherein anelastic member is provided inside the pressing tube to bias the clipmain body against the pressing tube in the distal direction, and theclip main body is moved in the distal direction with respect to thepressing tube by a bias force of the elastic member when the firstlocked portion is located more distal than the locking portion insidethe pressing tube.